CD8 + T cells (TCD8+) play a crucial role in eradicating viral infections. Despite this, little attention has been paid to the ability of vaccines to induce TCD8+ memory. For viruses in which traditional vaccine approaches have not been successful, it is hoped that induction of TCD8+ memory will enhance immunity. To induce optimal TCD8+ responses to vaccines it is necessary to understand how primary TCD8+ cells are stimulated. The goal of this project is to answer the following questions; 1. Following a virus infection in what anatomical location are primary TCD8+ cells stimulated (local sites of infection, lymph nodes, spleen)? 2. What type of cell presents antigen to primary TCD8+ cells? 3. Is the antigen presenting cell infected, or does it present viral proteins obtained from infected cells? 4. How does these answers to questions 1-3 vary between different antigens encoded by the same virus and the same antigen encoded by different viruses?